Casting apparatus

ABSTRACT

A casting apparatus. A body of granular material is confined in a container and a stream of gaseous fluid is introduced into the bottom of the container to impart to the granular material a state at least approaching fluidization. Into the thus-agitated material a form is introduced consisting of a material which is subject to consumption on contact with a molten metal. Admission of gaseous fluid is terminated to permit settling and compacting of the granular material about the form. Molten metal is introduced into the form to assume the configuration of the same while simultaneously consuming the form. The circumferential wall of the container is gas permeable and gaseous fluids in the container, particularly combustion gases resulting from the consumption of the material of the form, is aspirated through the gas-permeable circumferential wall to the exterior of the container.

United States Patent [72] Inventor Erich Krzyzanowski Frankenthal/Pialz,Germany 21 Appl. No. 830,326 22 1 Filed June 4, 1969 [45] Patented Jan.26, 1971 [73] Assignee Grunzweig & Hartmann AktiengesellschaitLudwigshaien (Rhine), Germany [32] Priority June 19, 1968 [33] Germany[31] 1,758,521

Continuation-impart of application Ser. No. 795,570, Jan. 31, 1969.

[54] CASTING APPARATUS 6 Claims, 1 Drawing Fig.

[52] US. Cl 164/255, 164/253, 164/34, 164/5, 164/7, 164/160, 164/169,164/180 [51] Int. Cl B22d 27/16 [50] Field of Search 164/255, 253, 34,35, 36, 5, 6,7,160,169, 180

[56] References Cited UNITED STATES PATENTS 1,369,182 2/1921 Moore SummyPrimary Examiner -J. Spencer Overholser Assistant Examiner-V. K. RisingAtt0rneyMichae1 S. Striker ABSTRACT: A casting apparatus. A body ofgranular material is confined in a container and a stream of gaseousfluid is introduced into the bottom of the container to impart to thegranular material a state at least approaching fluidization. Into thethus-agitated material a form is introduced consisting of a materialwhich is subject to consumption on contact with a molten metal.Admission of gaseous fluid is terminated to permit settling andcompacting of the granular material about the form. Molten metal isintroduced into the form to assume the configuration of the same whilesimultaneously consuming the form. The circumferential wall of thecontainer is gas permeable and gaseous fluids in the container,particularly combustion gases resulting from the consumption of thematerial of the form, is aspirated through the gas-permeablecircumferential wall to the exterior of the container,

CASTING APPARATUS CROSS-REFERENCES TO RELATED APPLICATIONS The presentinvention is a continuation-in-part of my copending application, Ser.No. 795,570, filed on Jan. 31, I969 under the title Method and Apparatusfor Making Castings."

BACKGROUND OF THE INVENTION The present invention relates to castingapparatus, and more particularly to casting apparatus utilizing acasting mold or casting form consisting of a material which will beconsumed by contact with molten metal.

In my aforementioned copending application I have set forth a method andan apparatus for making castings utilizing forms consisting of amaterial which will be consumed by contact with the molten metal. Asthere indicated, I provide a container in which I confine a body ofgranular material, and I thereupon admit into a bottom region of thecontainer a stream of gaseous fluid in such a manner as to agitate thegranular material and impart thereto a state which at least approachesfluidization. Thereupon I introduce the casting form into thethus-agitated granular material and terminate admission of the gaseousfluid so that the granular material settles about and into tightconformity with the casting form which latter may consist of a foamplastic or the like. Now the molten metal is introduced into the formand fills the same, assuming the configuration of the form whilesimultaneously consuming the material thereof. On completion of thecasting the gaseous fluid is again admitted into the bottom region ofthe container to agitate the granular material in order to facilitateremoval of the finished casting which is embedded in the body ofgranular material.

The apparatus disclosed in my copending application utilizes a containerhaving a bottom wall which is gas-permeable, with a pressure-equalizingchamber being located below the bottom wall so that the gas can beintroduced into this chamber and will escape from there through thegas-permeable bottom wall and into the interior of the container.

I have found this apparatus disclosed in my copending application, to bevery advantageous. However, it does have one disadvantage which requiresfurther improvement. Specifically, it is unavoidable that the hotcombustion gases which develop in the interior of the container duringthe molding operation, be aspirated downwardly through the gas-permeablebottom wall while admission of gaseous fluid therethrough is terminated,and thus entervinto the vacuum pump which is also provided andcommunicates with the pressure equalization chamber for the purpose ofapplying through the same and through the bottom wall an underpressureto the body of granular material in order to aid in more tightlycompacting the granular material about the form which has been embeddedin the granular material while the same was in the fluidized state orthe state approaching fluidization. Evidently, the entry of such hotcombustion gases into the vacuum pump would be damaging to the latter ifthere are larger quantities of such combustion gases liberated. Wherethe apparatus is on a small scale, and only small quantities of hotcombustion gases develop, the danger is relatively small but where theapparatus is on a larger scale, the vacuum pump could be prematurelydestroyed. This would mean the necessity for providing filters andcooling arrangements to prevent the entry of hot combustion gases intothe vacuum pump and this, in turn, would considerably increase theexpense of the apparatus as well as requiring increased maintenance.

SUMMARY OF THE INVENTION It is, accordingly, a general object of thepresent invention to overcome this disadvantage.

More particularly, it is an object of the present invention to providean improved apparatus of the type set forth in my above-mentionedcopending application.

Still more specifically it is an object of the invention to provide suchan apparatus wherein hot combustion gases are withdrawn from theinterior of the container in such a manner that they cannot cause damageto any components of the apparatus.

In pursuance of the above objects, and others which will become apparenthereafter, one feature of my apparatus resides in the provision of acontainer having a bottom wall and a circumferential wall which ispermeable to gaseous fluid. A body of granular material is confined inthe container. Admitting means is provided for admitting into thecontainer in the region of said bottom wall thereof a stream of gaseousfluid requisite for agitating the granular material to a state which atleast approaches fluidization. A casting form is arranged to beintroduced into the body when the granular material is in theaforementioned state, and consists of a material which is subjectconsumption on contact with the molten metal. Casting means is operativefor casting into the form a molten metal so that the latter assumes theconfiguration of the form while simultaneously consuming the same.Finally, I provide removing means operative for effecting withdrawal ofthe gaseous fluids from the container through the circumferential wallthereof.

This prevents the hot combustion gases, or at least the major portionthereof, from becoming aspirated through the bottom wall into the vacuumpump.

The novel features of the invention which are considered ascharacteristic of the invention are set forth in particular in theappended claims. The invention itself, however, both as to itsconstruction and its method of operation, together with additionalobjects and advantages thereof, will be best understood from thefollowing description of specific embodiments when read in connectionwith the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single FIG. is a diagrammaticillustration of apparatus according to my present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing indetail it will be seen that my novel apparatus comprises a container 1bounded by wall means which includes a gas-permeable bottom wall 2 and agas-permeable circumferential wall 10. The bottom wall 2 communicateswith a pressure-equalization chamber 3 located below it, and the latterin turn communicates via a conduit 5 with a conventional three-way valve6 of the type which is more fully discussed in my aforementionedcopending application. An operating member 6a serves to actuate thethreeway valve 6, and the latter can be made to connect the conduit 5selectively via conduits 5a with either a source of vacuum or a sourceof gaseous fluid, both being indicated in the drawing in diagrammaticform and with legends.

As shown, the interior of the container 1 accommodates a body ofgranular material, and a casting form CF is diagrammatically indicatedand is to be embedded in this body when the same has been placed into astate at least approaching fluidization by the admission of gaseousfluid from the source through the conduit 5 and the chamber 2 andthrough the bottom wall 2 into the interior of the container 1. Castingmeans CM, also illustrated diagrammatically, serves to introduce moltenmetal into the casting form CF after the same has been embedded to thenecessary extent in the body of the granular material. All of this isdescribed in more detail in my aforementioned copending application.

According to the present invention the circumferential wall 10 of thecontainer 1 consists of gas-permeable material, for instance of highlyheat-resistant porous sintered material, and the container 1 itself issurrounded by additional wall means 11 which defines with thecircumferential wall 10 an enclosed space, or enclosure, identified withreference numeral 110. This enclosure lla is fluidtight and communicateswith the ambient atmosphere in known manner via suitable removing means,here illustrated as a blower 12 whose intake communicates with theinterior of the enclosure 1 1a and whose outlet communicates with theexterior of the wall means 11, usually with the ambient atmosphere.

It will be noted that the enclosure 11a and the chamber 3 are fluidtightly separated from one another so that any hot combustion gaseswhich develop in the interior of the container 1 during the castingprocess are completely or at least substantially aspirated through thegas-permeable circumferential wall into the enclosure 11a and ventedfrom there via the removing means 12, preventing their aspirationthrough the permeable bottom wall 2 into the chamber 3 and from therethrough the conduit 5 into the vacuum source, usually a vacuum pump.

[n this manner I provide an apparatus which in a simple and inexpensivemanner improves the apparatus disclosed in my aforementioned copendingapplication and avoids the abovediscusscd disadvantage thereof inreliable manner.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in acasting apparatus, it is not intended to be limited to the detailsshown, since various applications, modifications and structural changesmay be made without departing in any way from the spirit of the presentinvention.

I claim:

I. An apparatus of the character described, comprising in combination, acontainer having a bottom wall, and a circumferential wall permeable togaseous fluid; a body of granular material confined in said container;admitting means for admitting into said container in the region of saidbottom wall thereof a stream of gaseous fluid requisite for agitatingsaid granular material to a state at least approaching fluidizationmeans providing said fluid stream; a casting form arranged to beintroduced into said body when said granular material is in said state,and consisting of a material subject to consumption on contact with amolten metal; casting means operative for casting into said form amolten metal so that the latter assumes the configuration of said formwhile consuming the same; and removing means operative for effectingwithdrawal of gaseous fluids from said container through saidcircumferential wall.

2. An apparatus as defined in claim 1, wherein said circumferential wallis composed at least in part of sintered metal.

3. An apparatus as defined in claim 1; further comprising wall meanssurrounding said container and defining with the same a fluid tightenclosure; and wherein said removing means are operative for withdrawingsaid gaseous fluid through said circumferential wall into said enclosureand for removing the withdrawn gaseous fluid from said enclosure to theexterior of said wall means.

4. An apparatus as defined in claim 3, wherein said bottom wall alsoconsists of material permeable to said gaseous fluid; said wall meansfurther defining a pressure-equalizing chamber located below said wallmeans, and said admitting means communicating with said chamber foradmitting said stream of gaseous fluid into the latter for passagethrough said bottom wall and into said container; and wherein saidchamber and said enclosure are fluid tightly separated from one another.

5. An apparatus as defined in claim 3, wherein said removing meanscomprise a blower having an inlet communicating with said enclosure andan outlet communicating with the exterior of said wall means.

6. An apparatus as defined in claim 4; and further comprising a sourceof underpressure communicating with said chamber for aiding in settlingand compacting of said granular material about said form subsequent tointroduction of the latter into said body and upon termination ofadmission of said gaseous fluid into said container.

2. An apparatus as defined in claim 1, wherein said circumferential wallis composed at least in part oF sintered metal.
 3. An apparatus asdefined in claim 1; further comprising wall means surrounding saidcontainer and defining with the same a fluid tight enclosure; andwherein said removing means are operative for withdrawing said gaseousfluid through said circumferential wall into said enclosure and forremoving the withdrawn gaseous fluid from said enclosure to the exteriorof said wall means.
 4. An apparatus as defined in claim 3, wherein saidbottom wall also consists of material permeable to said gaseous fluid;said wall means further defining a pressure-equalizing chamber locatedbelow said wall means, and said admitting means communicating with saidchamber for admitting said stream of gaseous fluid into the latter forpassage through said bottom wall and into said container; and whereinsaid chamber and said enclosure are fluid tightly separated from oneanother.
 5. An apparatus as defined in claim 3, wherein said removingmeans comprise a blower having an inlet communicating with saidenclosure and an outlet communicating with the exterior of said wallmeans.
 6. An apparatus as defined in claim 4; and further comprising asource of underpressure communicating with said chamber for aiding insettling and compacting of said granular material about said formsubsequent to introduction of the latter into said body and upontermination of admission of said gaseous fluid into said container.